Submarine signaling apparatus



April 27 1926.

H. RIEGGER SUBMARINE SIGNALING APPARATUS Filed May 6, 1921 Patented Apr. 27,- 1926.

, umro STATES PATENT FFICE.

& EALS KE, AKTIENGESELLSCHAFT, OF A. CORPORATION OF GERMANY.

SIEMENSSTADT NEAR BERLIN, GERMANY,

SUBMARINE SIGNALING APPARATUS.

Application flleli May 6,

To all whom it may concern Be it known that I, HANS Rrcocnn, a citizen of the German Empire, residing at Berlin-Charlottenbur Germany, have invented certain new and useful Improvements in Submarine Signaling Apparatus, of whichthe following is a specifications.

My invention refers to submarine signaling. As is known, oscillating systems have been employed as transmitters or receivers of submarine signaling apparatus, which consist of two parts acoustically coupled together. Iii using the term acoustic coupling, I refer to the degree of acoustic influence exerted by one oscillatory structure upon another. This influence is affected both by the natural frequencies of the coupled oscillatory bodies and by the relative proportions of the masses of these bodles. One of these parts may be set into and form a portion of the outer wall Off- H16 vessel, and carries the other part consisting for instance of the diaphragm of a microphone. These devices are as a rule tuned in such a way as to bring the periodicity of their natural oscillations into resonance with the periodicity of the waves to be received. For it is not intended to receive oscillations other than the desired signals. Such devices with acoustically coupled elements, however, invariably possess a second additional point of resonance which occasions disturbances. The object of my invention is a submarine signaling apparatus, the oscillating parts of which are coupled together in so loose a manner, as to obtain a one-wave system throughout, i. e. one which possesses only one single periodicity of oscillation, in which case of course both oscillating bodies must be tuned practically to the same frequency. As is well known, the two-wave character of the known signaling devices is produced by the first vibrating part which receives the sound waves, and which imparts its 45 vibratory energy to the second body. After the vibratory energy of the latter has attained-a certain maximum value, it reverts back to the first body. For this reason the amount of energy residing in either body decreases and increases periodically. This [feriodic increase and decrease forms the second undesirable natural-frequency. In-

1921. Serial No. 467,355.

contradistinction' thereto the loose coupling .betweenthe oscillating bodies according to the invention is attained by making the mass of the second oscillating part so small in comparison to the mass of the first part, as to .cause the energy transmitted to the second part to be absorbed by the dampmg efi'ect, before it can return to the first oscillating part.

If the second'oscillating part consists of a microphone, the construction of such a proportlon of masses is diflichlt to accomplish and for this reason it is preferable to employ a magnetophone in place of the microphone.

.- In'the drawings affixed to the specification and forming part thereof a sound receiver as embodying my invention is represented diagrammatically b way of example.

Referring to the drawings the diaphragm receives the incoming waves. The pin 8 1s fixed in the center of this diaphragm and forms a portion of the mass thereof and carries the second oscillating part of smaller mass, the leaf-spring f, its free end being operatively disposed adjacent to the permanent magnet g of the magnetophone. It converts the mechanical vibrations into electrlcal oscillatory currents which are induced 1n coil e and are conducted further to the re celver t. The essential idea of this invention is that the mass of the leaf-spring f is made so small in comparison to the mass of the diaphragm m that the system consisting of m and f only possesses one single natural frequency.

The damping, by which the energy transmitted to spring 7 is absorbed, as stated in the introduction .to the "specification, is due essentially to two causes. First, the air res stance which every element oscillating in air must overcome, and which is not useful and an absolute loss. Second, the useful damping due to the spring end oscillating in a magnetic field. Therefrom two effects result: First, eddy currents are induced in the spring, which, however, in case the.

spring is made quite thin, are so small that this source of damping may be neglected in practice. Second,through thespring oscillations the field of the magnet is varied so that currents are induced in coil e. This is the actual useful dampin because if the known heretofore which have more than one natural frequency.

I claim:

1. In a device of the character described the combination of two coupled oscillatory systems each system being tuned to the same frequency and one system carrying the other, the mass of one system being so small compared with the mass of the other system, that the total coupled combination .of the two systems has only one natural frequency, and means, operatively connected With the system of smaller mass, for rendering perceptible the oscillations of the combined systems.

2. In a device of the character described same frequency, the mass of said spring being very small compared with the mass of said diaphragm sothat the coupled system formed by said combination has only one single natural frequency, a permanent magnet disposed relatively to said spring so that the free end of the latter is located within the field of said magnet, and a coil on said magnet in which currents are induced when the magnet field varies due to the oscillations mg said currents.

In testimony whereof I aflix my signature.

HANS RIEGGER.

of said spring end, and means for perceiv-- 

